CN101458322B - Local positioning system and positioning method thereof - Google Patents

Abstract

The invention provides a local positioning system. A broadcasting antenna and a radar antenna are arranged at identical axial line of an identical launching positioning tower which is perpendicular to the ground surface, and the broadcasting antenna and the radar antenna use identical frequency while launching; or two launching positioning towers with different frequencies are arranged at points (A) and (B) with a preset distance respectively, and all scanning antennas on the antenna frames of the two positioning towers rotate in the clockwise direction. The invention relates to a technology of positioning a ground subject on ground surface, is applicable to a local scope from dozens and one thousand miles and has the characteristics that the precision is high, the equipment is easy to produce and the cost is relatively low.

Description

Local positioning system and localization method thereof

Technical field

The present invention relates to a kind of local positioning system of realizing based on the radiolocation technology, also relate to the method that this local positioning system is realized the location simultaneously, belong to the radiolocation technical field.

Background technology

Two during the last ten years, and GPS of America popularizes, and facilitated the army and the people's use, brought huge economic interests.In the car and boat location, the aspects such as navigation, electronic chart, accident relief, engineering construction, disaster prevention use very extensive.Russian GLONASS, European Union's Galileo and the Chinese big-dipper satellite positioning system in addition that are born subsequently.But there are many weak points in GPS promoting the use of middle discovery, existing abbreviated analysis explanation.

1.GPS belong to (location when essence is survey, range finding location.After time synchronized, the mistiming of passing to the measured point by the signal of four satellites be multiply by respectively the light velocity, then calculates the stereoscopic three-dimensional coordinate of measured point), require accurate timing.General receiving equipment, particularly vehicle-mounted or the handheld device accuracy of timekeeping is inadequate, so distance accuracy is relatively poor, be now 5-50 rice.In automatic navigator, automobile travels on road sometimes, and icon but is presented at place, 40 meters outer residential blocks, such precision, be hard to tell be road which side, in river which side or institute outside institute.Present GPS has signal interruption 2.5-2。The stall problem of 8 minutes.This causes because of the satellite layout is unreasonable.Gps satellite is six tracks, and four, every track causes the front satellite to fall behind the face satellite and also do not rise, and causes signal interruption.Third generation GPS will change three tracks into, 10 satellites of every track, and with compatible with Galileo system, erasure signal interrupts, and improves precision to 4-40 rice.

2.GPS frequency of utilization is decimetric wave, wavelength 16-27cm, and frequency 1100-1900MHz belongs to direct wave, but is difficult for penetrating cloud and mist.Penetrate the cloud and mist effect and be preferably superhigh frequency band, wavelength 3cm-10cm, frequency 1G-3000MHz, thus GPS can not be used for being automobile, steamer all weather navigation because of frequency problem and precision problem, particularly can not solve all weather navigation problem of takeoff and landing.

3.GPS can locate during the signal direct projection.When satellite position was in the oblique fire state, signal easily blocked for barrier, buildings.Therefore in electronic urban map used, the indoor signal that can not receive can't be located.Sometimes also no signal under housing-group and high-wall.

4. easily be disturbed.Apart from ground 21000-23000 kilometer, signal intensity is lower, easily is disturbed due to the track of position location satellite operation.The interference unit of 4w reaches 200 kilometers to the GPS interference range.

5.GPS the GPS reaction velocity is lower, nominal 0.25 meter per seconds are difficult to the instantaneous velocity of Accurate Measurement high-speed moving object.

6. global position system technical sophistication degree is high.GPS of America is not yet perfect through more than 20 years, and Russia did not complete networking in more than 20 year, and European galileo is not launched formal position location satellite so far.

7.GPS system is costly, cost is higher.

In sum, because there are many weak points in global position system, cause the research of founding local positioning system.

Summary of the invention

Primary and foremost purpose of the present invention is to provide a kind of local positioning system.This local positioning system is realized based on the radiolocation technology, is that the strong of global position system replenishes.

Another object of the present invention is to provide a kind of above-mentioned local positioning system to realize the concrete grammar of meridian tyre.

For realizing above-mentioned goal of the invention, the present invention adopts following technical scheme:

A kind of local positioning system is characterized in that:

Described local positioning system is included in a broadcast antenna and radar antenna of installing on the axis of same vertical ground of same positioning table;

Described broadcast antenna and radar antenna use same frequency when emission.

Described broadcast antenna is substituted by radar antenna, and in the case, the rotating speed of two radar antennas is different.

Described radar antenna is for horizontally rotating the focusing scanning antenna, and described broadcast antenna is fixed broadcasting scattering antenna.

A kind of local positioning system is characterized in that:

In described local positioning system, at 2 positioning tables of setting up respectively two different frequencies of (A), (B) of preset distance, the scanning antenna on two positioning table antenna holders is rotation in the direction of the clock all.

described local positioning system also comprises receiver, described receiver is by antenna, High Amplifier Circuit, detecting circuit, separation circuit, the pulse switch counter, display screen, electronic chart, the calculation of longitude ﹠ latitude the electric circuit constitute, wherein, above-mentioned two signals that the positioning table antenna is sent of antenna reception, be isolated the rear two groups of High Amplifier Circuits that enter respectively, detecting circuit, separation circuit is processed until resolve into positive spike pulse and negative spike pulse, described positive spike pulse and negative spike pulse enter respectively positive pulse switch counter and negative pulse switch counter is processed, calculate relative angle.Described electronic chart provides the distance of two positioning tables and the longitude and latitude parameter of locality (A platform), calculates the longitude and latitude of tested point by the calculation of longitude ﹠ latitude circuit, and shows on display screen.

Described local positioning system also comprises reserve position, and described reserve position is arranged on two same straight lines of positioning table and symmetric position outside two positioning tables.

A kind of meridian tyre method realizes based on above-mentioned local positioning system, it is characterized in that calculating based on following formula the coordinate of tested point:

Local positioning system provided by the present invention and localization method thereof for GPS, are the location technologies that solves on the ground terrain object, are applicable to the local scope in tens to 1,000 kilometers, have that precision is high, equipment is easy to make and lower-cost characteristics.

When adopting the dextrorotation set location mode, the full accuracy line be one centered by the mid point of (A), (B), the circular arc take AB/2 as radius.

When adopting when revolving set location mode, the full accuracy line be one vertical and divide the straight line of AB equally.

Local positioning system provided by the present invention and localization method thereof with respect to GPS, are the location technologies that solves on the ground terrain object, are applicable to the local scope in tens to 1,000 kilometers, have that precision is high, equipment is easy to make and lower-cost characteristics.

Description of drawings

Fig. 1 is the schematic diagram of two antenna transmit;

Fig. 2 is broadcasting scattering antenna and the radar antenna schematic diagram that transmits in 0 to 90;

Fig. 3 is the emission situations of A station two antennas in 0 ° to 90 °;

Fig. 4 is dual radars antenna transmission signal schematic representation;

Fig. 5 is in Δ ABM, and is known: c, and α, β asks the schematic diagram of the coordinate (x, y) that M orders;

Fig. 6 is in Δ ABM, and is known: AB=c, and ∠ A=90 °-α, ∠ B=β,

Find the solution: the schematic diagram of the coordinate (x, y) that M is ordered;

Fig. 7 is the complete structure schematic diagram of receiver;

Fig. 8 is the standard setting range computation figure of local positioning system;

Fig. 9 is maximum sample time of the schematic diagram of 90 ° of the different revolutions scanning situations of single radar antenna and adjacent revolution antenna scannings;

Figure 10 is that dextrorotation is the schematic diagram of full accuracy line;

Figure 11 is is the schematic diagram of full accuracy line to revolving;

Figure 12 is reserve position setting position schematic diagram;

Figure 13 is determining of stadia point (point of contact), the division schematic diagram of direct projection district and diffraction region;

Figure 14 is that flat pad height and sighting distance concern calculating chart

Figure 15 produces the error schematic diagram during diffracted wave is propagated at the earth's surface;on the face of the globe.

Embodiment

Local positioning system provided by the present invention is based on the radiolocation technology in the radio field, solves on the ground the technology of measuring the coordinate of each point in district to be measured.The localization method that this system adopts is to utilize known angle corner condition solving a triangle and the method for calculating this triangular apex coordinate, therefore local positioning system is the anglefinding position fixing technology; Simultaneously, predict the length of the length of side because of need, thereby define the scope in district to be measured, therefore be called local positioning system.

Local positioning system uses the anglefinding position fixing method, at first needs two position angles of Fast And Accurate Determination tested point.For this reason, the present invention is pioneering to this tested point rescan, this azimuthal method of Accurate Measurement.Adopt the way that shortens the rescan time interval to improve system to the velocity variations reaction capacity of high-speed moving object, the speed of 3 Mach/per second of energy Accurate Measurement.

In practice, local positioning system is subjected to the impact of radio wave propagation rule, and is subjected to the restriction of earth curvature, therefore in use be divided into 1.X, C, S-band direct projection district, i.e. line-of-sight propagation district.Be mainly used in all weather navigation of vehicle, naval vessels and takeoff and landing in 50 kilometers; 2.V wave band (direct projection district add diffraction region) is mainly used in locating among a small circle (in 100 kilometers) and long distance positioning (100 kilometers outer).

Below, this local of paper positioning system realizes that one of key method of meridian tyre-double antenna is same frequently with the arc angle-measuring method.

Shown in Figure 1, at the initial point (hereinafter to be referred as the A point) of meridian tyre, an antenna holder is set, two antennas of installing on the same axis of this antenna holder vertical ground, one one is fixed broadcasting scattering antenna; One one for horizontally rotating the focusing scanning radar antenna, in the direction of the clock rotation.This pattern is called broadcast antenna+radar antenna emission types.

Shown in Figure 2, when radar antenna went to 0 ° of direction, two antennas were simultaneously with start signal of same carrier frequencies emission.After this, scanning antenna is launched carrier signal continuously in 5 ° of-85 ° of scopes, and the scattering antenna does not transmit.When radar antenna went to 90 ° of directions, two antennas were launched again a termination signal simultaneously.

Signal receiver is equipped with micro-constant antenna frequently, the carrier signal (seeing Fig. 3) that reception A sends at the station.Only at 0 ° of direction (D o'clock on 0 ° of line), receiver could be accepted two start signals that antenna sends simultaneously in A station simultaneously.In figure, circular arc is all the isocentric circular arc take A point (A station) as the center of circle.Be a steady state value (V=299792458 meter per second) according to velocity of radio wave, any point on D point, M point and DM arc, receiver all can be at synchronization T _DReceive the start signal that the scattering antenna sends.

Like this, at the M point, before this at T _DConstantly receive the start signal that the scattering antenna sends, then elapsed time T, namely at T _MConstantly receive the sweep signal that radar antenna sends,

T＝T _M-T _D

Following formula explanation is adopted double antenna, with frequently, with the mode of arc, and the orientation for determining that M is ordered has found an initial time T _DWith one be scanned constantly T _M, and known scanning ripple the point time used is T from the D spot scan to M.According to the scan period of radar antenna, calculating scanning time of 1 ° is t, and so, T/t is the number of degrees of the number of degrees of DM and the right central angle ∠ A of DM arc:

For T _M, T _DConcrete time data need not measure (through having again one group of new data behind the interval blink), only need with representing T _DPulse open counter, with representing T _MPulse close counter.If the numerical value that the counter meter gets is m, scan that umber of pulse is n in 1 ° of corresponding time t, just m/n equals the number of degrees of ∠ A.If consider to use the forward position counting of pulse and rear along counting, can obtain two groups of data and get its mean value, will calculate more accurate to ∠ A like this.This process has also been completed the conversion from the analog form to the digital form.

Under aforementioned broadcast antenna+radar antenna pattern, if the radar rotating speed is changed, still can complete the accurate measurement that M is ordered.This just causes considers: if also change broadcast antenna into radar antenna, the moment that the inswept M of the radar antenna of two different rotating speeds is ordered is different, but exists each other certain relation.Utilize successively twice pair of scanning that M is ordered, can record the corresponding angle of M point.

Like this, on the antenna holder of A station setting, install A on the same axis of vertical ground ₁, A ₂Two radar antennas that model is identical with power, frequency of utilization is identical.This pattern is called dual radars antenna pattern.Antenna A ₁, with the rotating speed of 1 revolutions per second scanning, only working in first 90 ° weekly; Antenna A ₂With 2 times of rated rotational frequencies (2 revolutions per seconds) scanning, only work in first 90 ° of single-revolution.Two antenna coverage areas are identical, and starting simultaneously, but commencing signal no longer.

See Fig. 4, at the M point, receiver is before this at T _M2Constantly receive antenna A ₂The signal of emission; Then at T _M1Constantly receive antenna A ₁The signal of emission.Be T the interval time of two signals.Because of antenna A ₂Rotating speed is antenna A ₁2 times, so:

T＝T _M1-T _M2 T _M1＝2T _M2 T _M1＝2T＝2(T _M1-T _M2)

For T, T _M1, T _M2Need not measure etc. concrete time data, only need with representing T _M2Pulse open counter, with representing T _M1Pulse close counter.Institute's value is divided by the umber of pulse that comprises in 1 ° of Counter Design, then multiply by 2, namely obtains the number of degrees of the corresponding ∠ A of M point.

In sum, set up the emission positioning table at siting, on the same axis perpendicular to ground, press two antennas of upper-lower position installing, two antennas use same frequency work, and just rotating speed is different.By the principle with arc, the position angle that can record each point in district to be measured.This with two antennas on same axis, with frequently, with the mode of arc, azimuthal method that rescan is measured this point is carried out in the measured point, the inventor with its called after double antenna with frequently with arc angle-measuring method (also claiming the rescan angle-measuring method).Wherein, broadcast antenna+radar antenna pattern and dual radars antenna pattern all meet double antenna with requirement and the feature of frequency with the arc angle-measuring method, and can think, the former is the latter's custom design.

From two kinds of patterns relatively, can find out broadcast antenna+radar antenna pattern, only have the function of Accurate Measurement fixed object, and broadcast antenna is higher than radar antenna power consumption, therefore be difficult for accomplishing consistent on both power match and propagation distance.Dual radars antenna pattern have advantages of two antennas easily accomplish power match, signal propagation distance coupling, make easy for installation.Simultaneously, dual radars antenna pattern also has the function of rapid and accurate determination high-speed moving object instantaneous position.

The below continues to introduce this local positioning system and realizes one of key method of meridian tyre---and the two platform double frequencies of spacing are surveyed two angles localization method.

As can be known, to a triangle, know that this triangle can be separated with two angles (asa) that clip this edge in its limit from plane geometry and trigonometric function textbook.

As Fig. 5, in Δ ABM, known: AB=c, ∠ MAB=α, ∠ MBA=β does vertical line by the M point to AB, and intersection point is N, has

$Y=\frac{c}{\cot \mathrm{\α}+\cot \mathrm{\β}}=\mathrm{MN}$

$X=Y\·\frac{c\·\cot \mathrm{\α}}{\cot \mathrm{\α}+\cot \mathrm{\β}}=\mathrm{AN}$

If in rectangular coordinate system, the A point is true origin, and AB is on X-axis, and Y-axis is crossed the A point and perpendicular to AB, and the M coordinate of ordering is

$\left\{\begin{array}{c}X=\frac{c\·\cot \mathrm{\α}}{\cot \mathrm{\α}+\cot \mathrm{\β}}\\ Y=\frac{c}{\cot \mathrm{\α}+\cot \mathrm{\β}}\end{array}\right.$

Same frequently with the arc angle-measuring method according to double antenna, be c in distance ^KMA, B 2 points, set up the positioning table of two different frequencies, the scanning antenna on the antenna holder of two positioning tables is rotation in the direction of the clock all.As shown in Figure 6.Receiver is equiped with dual-band antenna and the corresponding binary channels calculation element that can receive simultaneously two of A, B.Record respectively ∠ A=90-α at the M point, ∠ B=β, by in Fig. 5 as can be known, ∠ A and α be complementary angle each other; ∠ B=β, β and (90-∠ B) be complementary angle each other, cot α=tan ∠ A, and cot β=tan (90-∠ β), so the M point coordinate can turn to:

Above-mentioned formula is exactly the core formula that the two platform double frequencies of spacing are surveyed two angles localization method.

For reaching degree of precision, should carry out laser ranging to A, B two positioning table axis spacings from c.So far.The M point coordinate obtains Accurate Measurement.

Fig. 6 has shown the receiver hardware structure diagram of this local positioning system.As shown in Figure 6, this receiver partly is comprised of antenna, High Amplifier Circuit, detecting circuit, separation circuit, pulse switch counter, display screen, electronic chart, calculation of longitude ﹠ latitude circuit etc.Wherein, above-mentioned two the positioning signal F that the positioning table antenna is sent of antenna reception _AAnd F _B, be isolated and enter respectively two groups of High Amplifier Circuits, detecting circuit, separation circuits and process afterwards, until resolve into positive spike pulse and negative spike pulse.Then, this positive spike pulse and negative spike pulse enter respectively positive pulse switch counter and negative pulse switch counter is processed, and calculates relative distance by above-mentioned formula.Electronic chart is responsible for providing the distance c of local two positioning tables and the longitude and latitude parameter of local A positioning table.Longitude and latitude parameter and the relative distance of electronic chart output are superposeed, can calculate by the calculation of longitude ﹠ latitude circuit longitude and latitude parameter of tested point, and show on display screen.

Lower mask body introduction is determined the circular of orientation range when using this local positioning system.Particularly, calculate A, two distances of B and calculate antenna transmission power and the field intensity of orientation range farthest, must make local positioning system standard setting range computation figure, referring to Fig. 7.Concrete computation process is as follows:

(1) selected centre of location O point;

(2) centered by the O point, be a as the length of side ^kmSquare GEFH;

(3) make diagonal line HE, GF, and extend;

(4) make as ray from the G point and become 5 ° of angles with GE, and hand over the HE extended line in A point (A platform position);

(5) make as ray from the H point and become 5 ° of angles with HF, and hand over the GF extended line in B point (B platform position);

(6) link AB, AB=c ^km

After standard setting range computation figure completes, as seen from the figure:

(1) centre of location is the O point;

(2) the locating rectangle length of side is a ^km

(3) location area is a ²Square kilometre; Can design accordingly the electronic chart scope;

(4) two emission positioning table distances are AB=c ^km=1.191754a ^km(select A, B platform location to use; Design circuit needs accurate measurement);

(5) AH=1.5498a ^km(design transmitting antenna power, ask orientation range farthest field intensity with).

The below continues to discuss some and improves the technical measures of this local Positioning System.

1. shorten sample time, make the angle measurement of high-speed moving object more accurate.

According to double antenna with frequently with arc angle-measuring method (rescan is decided the angle principle), to the stationary body in positioning area can Accurate Measurement the angle of its present position.But, to dynamic object, high-speed moving object particularly, the time interval of rescan will affect the precision of institute's measuring angle.This " time interval of rescan " is called " sample time ".Be engraved in variation during the position of moving object, its place, position angle is respective change also.So, must shorten as far as possible time interval of rescan, namely shorten sample time, just can make the angle that records more accurate.

First 90 ° that scan in each radar antenna per second are decided to be effective scanning scope (positioning area), and all the other are invalid scanning area.Situation when having drawn radar antenna from the independent scanning of 1 revolutions per second to 10 revolutions per seconds the first 90 ° in Fig. 8.And poor when also having drawn front 90 ° of two adjacent revolution antenna scannings.Because the scanning effective range is 90 ° to the maximum, therefore poor being called " maximum sample time " during with front 90 ° of two adjacent revolution antenna scannings.

When table 1 has been listed single radar antenna per second n revolution, scan 90 ° of times used.

It is n that table 2 has been listed same positioning table two radar antenna ratio of revolution: during n+1, and the maximum sample time when the unit radar antenna respectively scans 90 °.

Table 1

Table 2

It is n that table 3 has been listed ratio of revolution: the maximum sampling error (rice) under the maximum sample time during n+1 poor (second) and various speed.

Table 3

As can be seen from Table 3, in electronic urban map, 80 kilometers of automobile speed limits, 130 kilometers of Speed Limitation on Freeway, should select ratio of revolution is 2: 3, precision is less than 1 meter; The airport is taken off and sinking speed is 100 meter per seconds, and selecting the antenna ratio of revolution is 5: 6, and precision is less than 1 meter; When 3 Mach of movement velocitys, should select the antenna rotation rate ratio is 7: 8, and precision is less than 5 meters.

The listed maximum sampling error of table 3 is the data under maximum sample time.If object space is at 60 °, 45 °, 30 °, 22.5 °, and speed is when being 100 meter per second equally, and its sampling error will diminish, and be selected T as table 4 ₄: T ₅And T ₅: T ₆Comparative descriptions under condition.

Object place angle	Rotating ratio is s sampling error M 4: 5 sample times	Rotating ratio is s sampling error M 5: 6 sample times
			90°	1/80 1.25	1/120 0.83
60°	1/120 0.83	1/180 0.55
			45°	1/160 0.625	1/240 0.42
30°	1/240 0.417	1/360 0.28
			22.5°	1/320 0.3125	1/480 0.21

Table 4

2. concept and the application of district to be measured full accuracy line

District to be measured full accuracy line refers to respective antenna (A in two positioning tables ₁With B ₁A ₂With B ₂) in rotation, the line of synchronization sweep trace intersection point is called " full accuracy line "." synchronization " wherein means that two antennas should start to walk simultaneously, and like this, through synchronization, the angle that turns over is only equal.Therefore, must transmit a synchronizing pulse in the mode of wired, wireless or optical fiber, commander, the synchronous rotation of proofreading and correct two antennas namely make it synchronous.Certainly, absolute synchronization is impossible, need to provide a minimum synchronization accuracy.

In preamble, the antenna of A, two positioning tables of B is all adopted the clockwise direction rotation.At two identical antenna (A of the rotating speed of two of synchronizations ₁With B ₁A ₂With B ₂) inswept angle equates.The intersection point line of the sweep trace of two synchronized antenna synchronizations, be one take A, B two positioning tables apart from mid point as the center of circle, take 1/2nd semicircles as radius of A B distance c, as shown in figure 10.It is district to be measured full accuracy line that this circular arc is called dextrorotation.The original idea of full accuracy line is exactly in district to be measured, the point on the full accuracy line, and angle, the coordinate data precision of mensuration are the highest; Otherwise, the point from this line away from more, the angle of mensuration, the coordinate data precision is lower, error is larger.The full accuracy line of dextrorotation system is a circular arc.Proper for harbour, dam, bridge, electronic urban map, particularly the electronic chart for still life, low-speed motion location is comparatively suitable.

Make the sense of rotation of the antenna of two positioning tables, the A platform keeps dextrorotation constant, and the sense of rotation of B platform antenna changes into left-handed, and the antenna of two positioning tables is rotated relatively, and this mode is called and to revolving is.At synchronization, two two antenna (A that medium speed is identical ₁With B ₁A ₂With B ₂) inswept angle equates.The line of sweep trace intersection point, be one vertical and divide the straight line of two lines equally, as shown in figure 11.Be that the full accuracy line is a straight line that stretches to a distant place to revolving.If be that the full accuracy line overlaps with this to revolving, and adopt coordinate transformation method to the main runway centerline that falls in airport, the coordinate that becomes runway becomes x=0, and this will be very favourable for takeoff and landing.By contrast, main accuracy requirement of falling runway is the highest.

Above-mentionedly be dextrorotation system with the coordinate conversion in rectangular coordinate system or be the conventionally calculation that persons skilled in the art can be competent to revolving the coordinate that is, just do not describe in detail at this.

Next discuss that positioning table breaks down or the emergency measure when being destroyed.If positioning table breaks down or when being destroyed, especially large-scale civil airport or military airfield, must adopt emergency measure this moment, and emergency preplan is set up reserve position exactly.As shown in figure 12, reserve position should be based upon on the extended line of A B.Particularly, should start reserve position after 3-5 minute in A, the emission of B positioning table stop signal.For the aircraft of preparing landing, should inform the pilot when conversation, change the relevant parameters of receiver on aircraft.All receivers all should be debugged before use, are included as the software and hardware of alternative scheme design.

The below discusses the impact of earth curvature local area positioning system

As everyone knows, the earth is the oval ball that the two poles of the earth, north and south are slightly flat, slightly rouse in the equator.Earth polar radius is 6356.755km; Red radius is 6378.137km; Mean radius is 6371.004km.

It has been generally acknowledged that curvature is 360 °/(6371 * 2 π)=8.9932 * 10 ^-3Degree/kilometer

=8.9932 * 10 ^-6Degree/rice

=8.9932/thousand kilometers of degree

Electric wave is the same with light wave has diffraction (diffraction) effect.Higher than 300MHz, a little less than diffraction; Be decided to be rectilinear propagation or the sighting distance mode is propagated; Lower than this frequency, diffraction is stronger, is decided to be near linear and propagates, or think and can do over-the-horizon propagation.Its stadia point is " point of contact " of sight line and ground circular arc, as shown in figure 13.

Clearly, direct projection district part is subject to the impact of flat pad height (AA ').Be that sighting distance AP (or AP ') has certain relation (seeing Figure 14) with AA ' height (r).

$\cos \mathrm{\α}=\frac{R}{R+r},$ $\mathrm{\α}=\arccos \frac{R}{R+r}$

$\≈A^{\′}P$

In this local positioning system, use in the application of line-of-sight propagation district (direct projection) part, select " round-the-clock frequency range " the best.Its application will be divided into two kinds:

A. all weather navigation of airport takeoff and landing.The wave band that this moment is used is identical with the wave band of weather radar use fully.Requirement has stronger penetration power to cloud, mist, sleet, and enough sensitivity is arranged again.Use C-band, can reach effect preferably, frequency of utilization 6000MHz-5350MHz or wavelength 5cm-5.6cm.

B. all weather navigation of boats and ships in the harbor district of harbour.The wave band that this moment is used, the ability that requirement has the terrible weathers such as very strong anti-extra large noise jamming and anti-sleet to disturb requires to have higher precision and higher resolution.Specifically, use X frequency range medium frequency 9500MHz-8820MHz or wavelength 3.1cm-3.4cm.

In Figure 13,

Representative be the outer above ground portion of sighting distance, be (being the radar illumination blind area) that direct wave can not shine.But the V-band electric wave with stronger diffraction but can be right

Cover.Generally in the V-band 80MHz～120MHz band limits as example.Because this frequency range electric wave is to propagate having on the ground of certain curvature in the diffraction mode, by contrast, it has two characteristics: one. propagate farthest on the ground; Two. the flat pad height without strict demand, is needed only the front unobstructed.

The representative applications of diffracted wave part is ground and the water surface electronic chart of local positioning system.According to the characteristics of diffracted wave, desirable 30 meters high of positioning signal flat pad height, the position, point of contact is about 20 kms, and lower locating platform can be used in the location among a small circle, as the radar truck that flows, podium level 10-15 rice.

From the positioning principle of local positioning system, be based on the calculating of distance between two points on the ideal plane, space.But be the distance of calculating point-to-point transmission on spheroid (earth) surface in actual applications, this can produce error certainly.As Figure 15, the P point is the point of contact, R ₁For the space a bit; With PR ₁Draw arc for radius, hand over

In R ₂Point, PR ₁=PR ₂, but

Namely

Error

By following formula, calculate the error in hundred kilometers, as shown in table 5.

δ(cm)	1KM	2KM	3KM	4KM	5KM	6KM	7KM	8KM	9KM	10KM
											0KM	0.0001	0.001	0.003	0.007	0.01	0.02	0.04	0.05	0.07	0.10
10KM	0.13	0.18	0.23	0.28	0.35	0.42	0.50	0.60	0.70	0.82
											20KM	0.95	1.09	1.25	1.42	1.60	1.80	2.02	2.25	2.50	2.77
30KM	3.06	3.36	3.69	4.04	4.40	4.79	5.20	5.63	6.09	6.57
											40KM	7.08	7.61	8.16	8.75	9.36	10.00	10.66	11.36	12.08	12.84
50KM	13.62	14.44	15.29	16.17	17.08	18.03	19.02	20.04	21.09	22.18
											60KM	23.31	24.47	25.68	26.92	28.21	29.52	30.88	32.29	33.73	35.22
70KM	36.75	38.33	39.95	41.61	43.32	45.08	46.88	48.73	50.63	52.58
											80KM	54.57	56.62	58.72	60.86	63.06	65.32	67.62	69.99	72.39	74.86
90KM	77.38	79.96	82.60	85.29	88.04	90.85	93.72	96.65	99.64	102.70

Table 5

100～1050 kilometers errors table units of table 6 expression: rice

Distance	Error	Distance	Error	Distance	Error	Distance	Error
								100	1.0269	150	3.4659	600	222.0227	650	282.3314
200	8.2158	250	16.0474	700	352.6912	750	433.8822
								300	27.7321	350	44.0440	800	526.6858	850	631.8850
400	65.7480	450	93.6249	900	750.2647	950	882.6116
								500	128.4462	550	170.9867	1000	1029.7143	1050	1192.3634

Table 6

Can find out 1 meter of hundred kilometers precision, 150 kilometers 3.5 meters from table 5 and table 6.Obviously about 1 meter of error in 100 kilometer range, can consider.Hundred kilometers outer errors increase gradually, can by formula adjust.

Local positioning system provided by the present invention is mainly used in three aspects: 1. electronic chart, particularly electronic urban map; 2. the round-the-clock location navigation management of boats and ships in the harbor district of harbour; 3. all weather navigation of airport takeoff and landing management.

1. electronic urban map

Take electronic urban map as representative.

(1) orientation range.65 ^KM×65 ^KM，α＝65 ^KM AH＝65×1.55＝100.75

(2) frequency: 95-115MHz in V-band (whole nation is unified)

(3) antenna pattern: multicell combined type parabola antenna

(4) the antenna platform height is 30 meters

(5) emissive power: with distance platform 100 ^KMPlace's receiver sensitivity-85dB calculates

(6) antenna ratio of revolution: with city speed limit 80 ^KM/ h is standard, selects 2: 3.

(7) precision: 1 meter

(8) coordinate system: rectangular coordinate system, take the city meridian as Y-axis, monumented point is as (0,0) point on the meridian.

(9) Labeling Coordinate: press the four-quadrant mark: coordinate X ± XXXXX rice, Y ± XXXXX rice

2. the location navigation of boats and ships management in harbor district

The navigate mode of boats and ships enters into GPS navigation by beacon navigation, buoy navigation, radar navigation.But because being all coarse, isolated navigate mode, can not organically combine sea situation and surrounding environment, thus can not prevent stranded, hit a submerged reef, bump against, rollover etc. causes the perils of the sea to occur.

Local positioning system can make ships entered harbor obtain hi-Fix in harbor district, accurately and timely receive navigation signal, according to the accurate electronic chart of harbor district, avoids stranded, hits a submerged reef; In the situation that weather condition is relatively poor, receive caution, the warning of port square tube reason department, avoid bumping against, when sea situation changes, remind and avoid rollover; When occuring, other accidents also can in time be succoured.

Take Talien New Port as example.Select centered by front 5 kms of Talien New Port, draw the length of side and be the square positioning area of 17 kilometers.The anchorage is located to be in port front 9.25 kilometers (51 nautical miles), and the Frequent Accidents life is in the anchorage.Determine A, B 2 points according to location Calculation figure, at A, 2 antenna platforms of building high 60 meters of B, fix up an aerial wire.

To harbor district approximately 300 square kilometres of scopes make electronic charts.230 square kilometres of waters surface are indicated the depth of water, reef, shoal, waterborne and underwater obstacle and navigation mark with figure and symbol.Navigation channel, harbour, berth, anchorage etc.The electronic urban map standard is pressed on 60 square kilometres of Lu Qu ground, indicate buildings, warehouse, goods yard, road and other facilities with figure and symbol.

Large-scale receiving equipment peculiar to vessel comprises integrated receiver, and this ship position, the state of display screen demonstration take the Hong kong electronic chart as background arranged.Boats and ships are generally four antenna receptions, after the wide data of this captain of input, as long as two antenna work are arranged, and the just not demonstration of impact position, state.On electronic chart, represent that the figure of this ship can change and corresponding change map background with the coordinate of this ship, actual is that respective background oppositely moves.

Coordinate electronic chart can show the speed of a ship or plane, course, point out nearest barrier, shoal, reef distance, can issue the warning of this ship draft according to the electronic chart bathymetric data.

Before this ship's entry, open receiver, and other attached telecommunication apparatus, with harbour management equipment AutoLink, listen to the instruction of approaching, and automatically report this ship kind, ship type, the side of a ship number, order of classes or grades at school, this ship coordinate, course, the speed of a ship or plane, draft; Instruction, warning, the alarm of the issue of automatic reception harbour management department, the approaching warning of moving target and his ship approach should dodge indication.

Harbour management equipment comprises command and management screen and the auxiliary device thereof that shows the harbor district water surface.Display screen is a large-scale panorama electronic map, can show according to the information that each ship that approaches at the port is sent position, state, the motion conditions of these ships.Management equipment can be issued navigation instruction, stagnation of movement instruction, berth anchorage or berth instruction, can automatically issue two ship distances near alarm, transmits near simulation drawing to both sides, and prompting is dodged.Can issue weather forecast, disaster alert, wind, rain, mist, snow, night are round-the-clock to implementing at the port boats and ships, the round-the-clock management.

3. all weather navigation of airport takeoff and landing

The all weather navigation of airport takeoff and landing is one of important application of local positioning system.It can solve GPS found since 20 years this there is no the problem that can solve.The U.S. abandon GPS need not, then research uses airborne microwave radar to solve aircraft " blind landing " problem when weather visibility is extremely low.U.S. government issues the equipment list that prohibits selling to China and just comprises this microwave airborne radar.Local positioning system solves all weather navigation of airport takeoff and landing in the mode of facade electronic chart.

(1) orientation range: 17 ^KM* 17 ^KMA=17 ^KMAH=27.7M

(2) frequency: all-weather electronic map C-band, wavelength 5-5.6cm, frequency 6000MHz-5350MHz (whole nation is unified); Attached ground electronic chart (being different from the electronic urban map frequency of utilization) V-band 100-120MHz (whole nation is unified)

(3) antenna pattern: double frequency parabolic cylinder multicell combined type (C, V transmitter unit alternate)

(4) positioning table transmitter in airport is by being design to revolving

(5) the antenna platform height is 60 meters

(6) emissive power: 30 km field intensity-85dBm are as the criterion with the distance platform

(7) antenna ratio of revolution: 5: 6, rate accuracy: 0.83 meter

(8) electronic chart precision: 1 meter

(9) coordinate system: three-dimensional rectangular coordinate system: rectangular coordinate system, runway centerline (Y-axis) intersection point falls as true origin (0 take emission positioning table A, B line (X-axis) with main, 0), the main runway overhead aircraft altitude table that falls is surveyed height (h) and is H, formation 3 D stereo coordinate system.But in use, only use planimetric coordinates projection (x, y) and facade coordinate projection (y, h), by two LCDs displaing coordinate data.

(10) the airport panorama electronic map should comprise landform, the atural objects such as airport neighbouring mountain peak, forest, river and high building, steel tower, and the obstacle of impact flight is wanted special suggestion.

The height indicator that precision reaches 1 meter all is installed on every airplane, and its altitude information of surveying is H, and the X that it and local positioning system receiver are measured, Y data consist of three-dimensional coordinate;

Be true origin (0,0) at positioning table A, B line (X-axis) and the main intersection point that falls runway centerline (Y-axis), the coordinate of Y-axis be (0, Y).From true origin outwards, Y-axis left side is for negative, and the Y-axis right side is for just.On X Y plane, the projection of aircraft coordinate will be presented on the plane projection liquid crystal display.The primary runway center line of aircraft landing, coordinate are that (0, Y), and Y and aircraft altitude table data H consist of one group of facade projection's data, are shown by facade projection's liquid crystal display.Must be noted that, Y, H data be forever on the occasion of.

Aircraft is got in touch with airport management and control department when entering the airport, agrees to enter terminal airspace and spirals and wait to fall.Aircraft should be opened telecommunication system and link with the airport relevant devices, listens to navigation instruction; By the supervisory routine requirement, automatically send the elements of a fix, flying height, flying speed and other data (flight, personnel, load-carrying, existing fuel oil, Plant in good condition situation, failure condition etc.) take time sequencing as benchmark;

Spiral in designated flying zone, runway left side before landing and wait to fall, height is below 5000m, more than 1500 meters; Receive the landing instruction, line up with runway rapidly reduces height, and beginning to fall is highly 1000 meters (3280 feet).

Two display screens are established in aircraft instrument dish top, a display plane perspective view, and one shows the figure of facade projection.After aircraft is down to 1000 meters, to put down when flying to appointment underriding level point, electronic chart is reminded and is begun to dive, and electronic chart is automatically switched to magnifying state, is beneficial to line up with runway.After aircraft lands, electronic chart is switched back general state.

Position (Y can be determined to begin to fall according to the situation of oneself in the airport _J, H _J) and aircraft landing after sail out of the route of runway (beginning fall position available electron map and shows; The route that sails out of runway can send instruction temporarily).

In the aircraft landing process, facade display per second shows a new coordinate points and remains, and consists of one group of complete landing track data, reference when giving over to design or check landing data.

Dropping zone facade enlarging projection electronic chart has the function that records this landing track, while also has record and shows the function of the various parameters in this landing process, as level speed, underriding angle, each point coordinate of landing track, when being down to how many height with the head pull-up, during pull-up, the elevation angle must not surpass 12 °, in order to avoid wipe tail etc.

Above local positioning system of the present invention and localization method thereof are had been described in detail, but obvious specific implementation form of the present invention is not limited to this.For the those skilled in the art of the art, in the situation that do not deviate from various apparent change that claim scope of the present invention carries out it all within protection scope of the present invention.

Claims (9)

1. local positioning system based on the radiolocation technology, its feature is as follows,

At 2 positioning tables of setting up respectively two different frequencies of (A), (B) of preset distance, a broadcast antenna of installing and a radar antenna on the axis of the same vertical ground of same positioning table, described broadcast antenna and radar antenna use same frequency when emission; Two four of positioning tables antennas are regularly to emission radiowave in district's to be measured, receiver receives radiowave at tested point, utilize ' double antenna is same frequently with the arc angle-measuring method ' and ' the two platform double frequencies of spacing are surveyed two angles localization method ', and try to achieve tested point two position angles with the priority secondary singal of every positioning table, and then obtain the position coordinates of tested point according to formula according to the known distance between two position angles and two positioning tables.

2. local positioning system as claimed in claim 1 is characterized in that:

Described radar antenna is for horizontally rotating the focusing scanning antenna, and described broadcast antenna is fixed broadcasting scattering antenna.

3. local positioning system as claimed in claim 1 is characterized in that:

Described broadcast antenna is substituted by radar antenna, and two radar antenna rotating speeds on same axis are different, but the corresponding radar antenna of two positioning tables (A1 and B1, A2 and B2) rotating speed is identical.

4. local positioning system as claimed in claim 1, it is characterized in that: described local positioning system also comprises reserve position, be arranged in two same straight lines of positioning table on, and two positioning tables outsides symmetric positions.

5. local positioning system is characterized in that:

In described local positioning system, at 2 positioning tables of setting up respectively two different frequencies of (A), (B) of preset distance; A broadcast antenna of installing and a radar antenna on the axis of the same vertical ground of same positioning table, described broadcast antenna and radar antenna use same frequency when emission; Only on 0 ° of direction, receiver could be accepted the start signal that two antennas send simultaneously simultaneously, after this, and according to " double antenna is same frequently with the arc angle-measuring method ", two position angles of measuring respectively tested point; In described local positioning system, the radar antenna on two positioning table antenna holders is at the uniform velocity rotation in the direction of the clock all.

6. local positioning system as described in claim 1 or 5 is characterized in that:

Described local positioning system also comprises receiver, and described receiver is by antenna, High Amplifier Circuit, detecting circuit, separation circuit, pulse switch counter, display screen, electronic chart, calculation of longitude ﹠ latitude the electric circuit constitute; Wherein, above-mentioned two positioning signals that the positioning table antenna is sent of receiver antenna reception are isolated and enter respectively two groups of High Amplifier Circuits, detecting circuit, separation circuits and process afterwards, until resolve into positive spike pulse and negative spike pulse; Described positive spike pulse and negative spike pulse enter respectively positive pulse switch counter and negative pulse switch counter is processed, and calculates relative angle; Described electronic chart provides the distance of two positioning tables and the longitude and latitude parameter of locality (A point), calculates the longitude and latitude parameter of tested point by the calculation of longitude ﹠ latitude circuit, and shows on display screen.

7. meridian tyre method, realize based on local positioning system as described in any one in claim 1-6, it is characterized in that being sent in mechanical motion by emitting antenna electronic signal, receiver receives positioning signal, two position angles of accurate Calculation tested point are also completed based on following formula and are calculated, employing dextrorotation system, i.e. all rotations in the direction of the clock of radar antenna, thus complete simulating signal to the transformation of digital signal; In the triangle of positioning table A, positioning table B and tested point M formation: ∠ A, ∠ B are the position angle that records, and c is known A, B spacing, and the coordinate M (X, Y) of tested point is:

8. meridian tyre method as claimed in claim 7 is characterized in that:

The corresponding radar antenna of two positioning tables (A1 and B1, A2 and B2) rotating speed is identical, when two radar antennas turn clockwise, when adopting dextrorotation to be localization method, the full accuracy line be one centered by the AB mid point, the circular arc take AB/2 as radius.

9. meridian tyre method as claimed in claim 7 is characterized in that:

The corresponding radar antenna of two positioning tables (A1 and B1, A2 and B2) rotating speed is identical, when two radar antennas, and the turning clockwise of left side, being rotated counterclockwise of right side adopted revolving when being localization method, and the full accuracy line is vertical and divides the straight line of AB equally.

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